EFFECT OF CTJLTUKE AND CLIMATE ON PEPPEEMIKT OIL. 3 
from the plants grown at Glenn Dale, Md., and Arlington Farm, Va., 
since these are but a few miles apart and the general climatic con- 
ditions are practically the same in both localities. 
Table I. — Comparison of yields and physical composition of peppermint oils distilled 
from plants grown in several localities on various types of soils. 
Yield, 
of oil. 
Physical properties. 
Chemical composition (per 
cent). 
Locality and soil. 
Color, odor, and 
Spe- 
cific 
Rota- 
tion, 
Re- 
frac- 
tion. 
Solubil- 
ity in 80 
Free 
acid 
Free 
esters 
(men- 
Menthol. 
taste. 
grav- 
50 mm. 
per cent 
(as 
thyl 
ity. 
tube. 
alcohol. 
acetic). 
ace- 
Free. 
Total. 
tate). 
P.ct. 
o 
Voluw.es. 
Arlington Farm, 
0.12 
Pale yellow; 
aO.9203 
-10.6 
& 1.4662 
el.2 
0.21 
7.07 
46.5 
51.7 
Va. (heavy clay 
agreeable men- 
soil). 
thol-like odor . 
Do 
.13 
Pale yellow ; 
mild, agree- 
a. 9273 
— 5.7 
a 1.4820 
d .6 
.03 
11. 67 
30.94 
40.13 
able, minty 
odor; fatty, 
cooling, pun- 
gent taste. 
Pale straw; 
Webster, S. Dak. 
.10 
a. 9280 
- 8 
& 1.4715 
<*1.5 
.05 
9.9 
46.48 
54,28 
(rich black 
pleasant flow- 
loam). 
ery odor; pun- 
gent, mmty, 
cooling taste. 
Glenn Dale, Md. 
.11 
Pale yellow; 
a. 9403 
-10 
el.4735 
d.8 
.75 
23.34 
35.89 
54.28 
(light sandy 
agreeable aro- 
soil). 
matic, minty 
odor; bitter, 
slightly pun- 
gent, cooling 
taste. 
a At 22° C 
& At 25° C 
c Turbid in 2 volumes or more. 
d Turbid in 2\ volumes or more. 
e At 23° C 
YIELD OF OIL FROM FRESH AND FROM DRY PLANTS AT VARIOUS 
STAGES OF GROWTH. 
In order to study the effect of the time of harvest upon the yield 
and quality of peppermint oil and also the yield of oil as obtained 
from fresh and dry plants, experiments were conducted through a 
series of years, from 1908 to 1912, inclusive. The plants were har- 
vested at three distinct stages of growth, namely, the budding, flow- 
ering, and fruiting stages, and the oil was distilled from both the 
fresh and the dried plants. A comparison was made of the various 
oils, the results being shown in Table II. 
The yield of oils distilled from the fresh plants during the budding 
stage shows considerable variation, the yield in 1908 being especially 
high. During 1909, 1910, 1911, and 1912 considerably less variation 
is observed. Similar deviation during the flowering stage is to be 
noted, the yield in 1908 again being noticeably higher. More uni- 
formity is apparent in the results obtained from the fruiting plant. 
In two of the seasons mentioned (1909 and 1911) the yield of oil 
during the fruiting stage was slightly in excess of that from either 
the budding or the flowering stage. 
